1.1 Understanding the importance of having a transport system in some multicellular organisms.

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Presentation on theme: "1.1 Understanding the importance of having a transport system in some multicellular organisms."— Presentation transcript:

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1.1 Understanding the importance of having a transport system in some multicellular organisms

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Organisms that are small in size have a large total surface area to volume (TSA/V) ratio. Large organisms have a small TSA/V ratio. Hence, the rate of diffusion is higher in small size organisms than the large ones.

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1.1 Understanding the importance of having a transport system in some multicellular organisms (cont’d) Unicellular organisms my obtain their nutrients and oxygen by diffusion alone but multicellular organisms are more complex and bigger in size. Thus, they need a special transport system to transport the nutrients and oxygen to the body cells. The transport system in humans and animals are called the circulatory system. The transport system in plants are the vascular tissue which consists of xylem and phloem tissues.

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1.2 The concept of circulatory system

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The circulatory system in humans and animals consists of blood, blood vessels and heart. Blood is the connective tissue in liquid form. The human blood is made up of 55% plasma and 45% blood cells.

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Plasma ConstituentsMajor functions WaterSolvent for transporting dissolved substances such as glucose IonsMaintain osmotic balance in the blodd and pH of the blood at 7.4 Plasma proteins Albumin Fibrinogen Immunoglobulins Maintain osmotic balance, and act as buffers against pH changes. Fibrinogen is involved in the clotting of the blood. Immunoglobulins are antibodies that help in the body’s defence. HormonesControl physiological activities of the body Dissolved substancesNutrients that are essential for the body

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ArteryCapillaryVein Located deeper in the body Between arteriole and venule Located near skin surface Thick muscular wallThin wall, one-cell thickThin wall, less muscular Small lumenVery small lumenBig lumen No valves (except pulmonary artery) No valvesValve is present (except pulmonary vein) Blood flow very fast, at high pressure Blood flows is slow, at pressure decreases Blood flow is slow, at low pressure

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1.2 The concept of circulatory system (cont’d) Blood is propelled through the whole body by forced produced from the pumping of the heart and contraction of skeletal muscle. The heart is made of strong cardiac muscle. Cardiac muscle Interconnected, allow signals to be conducted rapidly Myogenic, contract spontaneously without nervous stimulation

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1.2 The concept of circulatory system (cont’d) Contraction of the heart is controlled by sinoatrial node (SA node) a.k.a pacemaker. Impulse from SA node move to atrioventricular node (AV node). Then, it moves through bundle of His fibres, bundle branches and Purkinje fibres.

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SA Node generate electrical impulse. The electrical impulse spread rapidly over atria, causing atria to contract Electrical impulse reach AV node, the pass to the ventricles, causing it to contract simultaneously. The whole atria and ventricles relax and the pressure in the heart is lowered. Blood moves into both atrium.

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1.2 The concept of circulatory system (cont’d) Skeletal muscle are usually located around the veins. Contraction and relaxation of the muscles enables the blood to flow Valves ensure the blood to flow in one direction

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1.2 The concept of circulatory system (cont’d) Blood pressure is the pressure exerted by the blood on the walls of the blood vessels. Normal blood pressure is 120/80 mmHg. 120 mmHg = systolic pressure 80 mmHg = diastolic pressure Blood pressure is regulated by baroreceptors (pressure receptors) in aorta and carotid arteries.

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1.2 The concept of circulatory system (cont’d) Open circulatory system Haemolymph is pumped into cavity around the cells Insects have a tube-shaped heart called ostia. Materials are exchanged between haemolymph and bode cells through diffusion.

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Closed circulatory system Blood is confined in one vessel One or more hearts pumped blood into major vessels that branches into smaller vessels

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1.2 The concept of circulatory system (cont’d) Single closed circulatory system Blood flows into the heart only once Blood is pumped by the heart to the gills, body tissues and back to heart again. The heart of a fish is simple; only one atrium and one ventricle.

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1.2 The concept of circulatory system (cont’d) Double -closed incomplete circulatory system Blood flows into the heart twice. Heart has two atrium and one ventricle. The oxygenated blood and deoxygenated blood is mixed in the undivided ventricle.

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1.2 The concept of circulatory system (cont’d) Double -closed complete circulatory system Blood flows into the heart twice. Heart has two atrium and two ventricle. Made up of two main circulation 1. Pulmonary circulation Deoxygenated blood is pumped into the pulmonary arteries 2. Systemic circulation Blood is pumped to the whole body

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1.3 The Mechanism of Blood Clotting

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Importance of blood-clotting To prevent blood loss To prevent the entry of microorganisms and foreign particles into the body To maintain blood pressure To maintain the circulation of blood in a closed circulatory system

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Interstitial Fluid Blood arrives at the capillary with high hydrostatic pressure Force some of the plasma to pass across the thin-membrane to fill the space between cell. This will form interstitial fluid. Contains water, dissolved nutrients, hormones, waste products, gases, small proteins.

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1.4 The Lymphatic System (cont’d) 90 % of the interstitial fluid diffuses back into the blood capillaries 10 % of the interstitial fluid diffuse into the lymph capillaries of the lymphatic system.

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1.4 The Lymphatic System (cont’d) Lymph flow to two main lymphatic vessels; 1. Thoracic duct Will enter the circulatory system via the left subclavian vein 2. Right lymphatic duct Will enter the circulatory system via the left subclavian vein

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1.4 The Lymphatic System (cont’d) The flow of lymph is aided by a few factors such as: Contraction of smooth muscles in the wall of lymphatic nodes Contraction of skeletal muscles when body moves Peristalsis movement in the alimentary canal Breathing movement The pulses in blood vessels

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1.4 The Lymphatic System (cont’d) The role of the lymphatic system Collect the interstitial fluid and return in into the circulatory system Defend the body against disease by producing lymphocytes Transport lipid, glycerol and fat soluble vitamin A, D, E dan K Transport water, hormones, glucose, amino acids, minerals and heat in the interstitial fluid Transport waste products such as carbon dioxide and nitrogenous compounds in the interstitial fluids

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1.4 The Lymphatic System (cont’d) Comparison among the blood, interstitial fluid and lymph. ContentBlood Interstitial fluid Lymph Water Small molecules like glucose, amino acids and minerals Large molecules like eryhtrocytes, platelets and plasma protein Lymphocytes